Simultaneous monitoring of each component on degradation of blended bioplastic using gas chromatography-mass spectrometry.

The increasing interest in bioplastics, with regard to future environmental issues, has rendered research on bioplastic biodegradation highly important. However, only a few tools directly monitor the degradation of bioplastics without measuring the levels of gaseous products, such as carbon dioxide. Classical nonquantitative methods, such as clear zone tests on solid plates, and less-sensitive weight-loss experiments in liquid media measured using a precision scale, are still employed to screen the microbial players associated with bioplastic degradation and monitor the biodegradation rates. However, the simultaneous monitoring of the degradation of each component of blended bioplastics has not been previously reported. In the present study, to provide information regarding the degradation rates and compositional changes of different bioplastics in a blend in a time-dependent manner, we simultaneously monitored and quantified the degradation of four bioplastics, polyhydroxybutyrate (PHB), polybutylene succinate (PBS), polycaprolactone (PCL), and poly(butylene adipate-co-terephthalate) (PBAT), by Bacillus sp. JY36 using gas chromatography-mass spectrometry (GC-MS) analysis after fatty acid methyl ester (FAME) derivatization. Our results demonstrate the feasibility of using the GC-MS-based method described here to obtain comprehensive data regarding blended bioplastics and their degradation. Moreover, our findings indicate that this method may support classical analytic tools for assessing bioplastic biodegradation.

Clinical study of Korean glaucomatous patients

In order to determine the distribution of each type of glaucoma in Korea, a retrospective clinical study was carried out on 206 glaucomatoils patients (295 eyes) who were followed from July 1982 to December 1985 in theClaucoma Clinic of the Department of Ophthalmology of Hanyang University Hospital. The distribution of glaucomatous patients was as follows; 34.0% primary open-angle glaucoma (POAG),32.5% secondary glaucoma,20.9% primary angle-closure glaucoma (PACG),7.3% ocular hypertension,3.9% congenital glaucoma, and 1.5% low tension glaucoma. In serondary glaucoma, glaucoma associated with uveitis occurred most frequently, and aphakic glaucoma, neovascular glaucoma, steroid-induced glaucoma, pigmentary glaucoma and exfoliative glauroma followed. The acute stage of PACG presented the highest initial IOP, 55.2+/-8.4mmHg, where as the initial IOP of POAG patients was 33.4+/-15.5 mmHg. Sixty-two per percent of POAG and 98% of PACG patients were over 40 years of age, and the mean age of the POAG and PACG patients was 43.1+/-16.3 and 61.6+/-9.5 years, respectively. There was no remarkable sex-difference associated with glaucoma, in PACG which showed an incidence of 79.1% in females. There was no significant difference in laterality between the right and left eyes with either glaucoma or ocular hypertension. Bilateral involvement of POAG and PACG during the follow-up period was 7l.4% and 32.6%, respectively.

Clinical Study on Korean Glaucomatous Patients

A clinical study was carried out on 206 glaucomatous patients(295 eyes) from July 1982 to December 1985 in the Department of Ophthalmology of Hanyang University Hospital. The results were as follows: 1. The glaucomatous patients consisted of 34.0% of primary open angle glaucoma(P.O.A.G.), 32.5% of secondary glaucoma, 20.9% of primary angle closure glaucoma(P.A.C.G.), 73% of ocular hypertension, 3.9% of congenital glaucoma and 1.5% of low tension glaucoma. 2. The mean intraocular pressure(IOP) of P.O.A.G. and acute stage of P.A.C.G. was 33.4 +/- 15.5 and 55.2 +/- 8.4mmHg, respectively. 3. 43.1 +/- 16.3 years was the mean age of P.O.A.G. and 61.6 +/- 9.5 years was that of P.A.C.G. 4. In overall glaucomatous patients there was no remarkable sex-difference except P.A.C.G. which showed higher prepondrence of females. 5. There was no significant difference in laterality between left and right eyes with glaucoma or ocular hypertension.

Clinical Evaluation of Oculokinetic Perimetry

Visual field examination plays an important role in the diagnosis of ocular and neurological disorders. Visual field screening devices have become popular because they require less time than quantitative perimetry, are easier for both the patient and examiner to perform, and can be administered to a larger number of patients. However, these instruments are expensive and in need of specific equipment. To eliminate these disadvantages, Oculokinetic perimeter was designed by Bertil E. Damato. Oculokinetic perimetry can be performed with rapid and simple method and we examined the visual field by Oculokinetic perimeter and compared the results with those using the Goldmann perimeter and Autofield-D static perimeter.

Ultrastructural and Immunofluorescent Features of Lymphatic Disorders in Conjunctiva

We have experienced one case of lymphangioma and one case of lymphangiectasia which was diagnosed with the histopathologic studies, including immunofluorescent and electron microscopic methods. The distribution of Ig G and Ig A within the stroma was shown, particularly in the inflammatory cells. The endothelial lined lymphatic vessel consisted of interrupted basal lamina and absence of pericyte on electron microscope.

Growth Patterns of Human Retinal Pigment Epithelium in Vitro

The in vitro growth pattern of the human retinal pigment epithelial cell was carried out from enucleated eye. The cultured cell was observed serially under phase contrast microscopy and stained for light microscopy. The cultured retinal pigment epithelium no longer resembled the original pattern of the retinal pigment epithelium and lost pigment granules as tissue culture progressed. This work has shown that the retinal pigment epithelium was viable and possessed proliferative potency for up to 36 days after seeding without subculture.

Clinical Observations on Hyper II(R) Soft Contact Lens

To estimate the clinical usefulness of a newly developed soft contact lens, Hyper II(R) soft contact lens which is a product of 2-hydroxyethylmethacrylate and special cross linking agents by International Contact Lens Lab., Seoul Korea, clinical observations were carried out in 89 patients(154 eyes) during the follow up period of 3 months from April 1985 to February 1986. Excellent corrected visual acuity(over 1.0) was obtained in 134 eyes(87%). The most common subjective symptom after wearing contact lens was foreign body sensation, but this symptom had diminished during the follow up period. Twentyfour eyes discontinued wearing the lens because of lens related problems including lens deposit(11 eyes), lens lost(3 eyes), foreign body sensation(3 eyes), handling difficulty(2 eyes), lens torn (1 eyes) et al. It can be suggested that Hyper II(R) soft contact lens is clinically available with excellent improvement of visual acuity and few complications, either subjective or objective, which might influence wearing contact lens. Long-term follow up, however, might be necessary to understand and reduce the late complications of this soft contact lens.